It is a law that all motor-driven vehicles must be provided with a rear-view-mirror, so that the driver of said vehicle can observe vehicles which are moving behind the vehicle which he is driving.
Motor-driven vehicles, however, are permitted to tow a trailer, for example a caravan, and since these trailers may have a width which exceeds the width of the towing vehicle, it is impossible, with conventional rear-view-mirrors, to observe following traffic. In order to eliminate this disadvantage it is stipulated that a motor-driven vehicle towing a trailer, whose width exceeds the width of the motor-driven vehicle, shall have a specially designed rear-view-mirror arrangement, which enables the driver to observe the following traffic,. This special rear-view-mirror arrangement necessarily extending a considerable distance from the side of the motor-driven vehicle.